High-voltage dry valve apparatus



July 24, 1951 u. LAMM ET AL HIGH VOLTAGE DRY VALVE APPARATUS Filed April 20, 1948 Patented July 24, 1951 HIGH-VOLTAGE DRY vALvE APPARATUS Uno Lam and Algot Arvidsson, Ludvika, Sweden, assignors to Allmarma Svenska Elektriska 'Aktiebolaget, Vasteras, S

poration weden, a Swedish cor- Application April 20, 1948, Serial No. 22,085 In Sweden April 22, 194:7-

4 Claims. (01. 175-366) voltages than some tens of volts, the low price of such element makes it possible to employ them commercially for blocking voltages up to hundreds of kilovolts by connecting a corresponding number of elements in series. For moderate voltages, up to the order of 1000 volts, a corresponding number of plates is assembled into a column, but for essentially higher. voltages the question arises how the elements should most appropriately be assembled. Since the high voltage dry valve apparatus are generally made for low currentsmost freduently below 1 ampere-and therefore with small surfaces of the semi-conducting layer, it is generally not advisable to employ a through bolt in each column, as such a bolt would require too much relative space and as the provision of a central hole in the valve plate would unnecessarily complicate its production. For guiding and assembling the plates of a column, they have generally been placed in a surrounding type of insulating material, but hereby the cooling of the plates will be rather poor.

According to the present invention, the dry valve plate columns, which have nov through bolt, are arrangedin such way that electrically seriesconnected columns are in a large number geomet-' rically parallel and separated 'by parallel rods of insulating material which facilitate the circu lation of a cooling medium transversely between the columns and through interspaces which may be provided between the individual plates and the columns. The rods may be cylindrical and in such case with respect to the manufacture (or Bakelite or the like) generally tubular, but they may also be prismatic, for instance formed between longitudinal slits in a Bakelite tube, such slits being so wide that the cooling medium can circulate substantially freely through the interspaces between the plates. The rods should have a limited length or be connected by reinforcing parts at certain intervals in order to give the 2 may engage or which are traversed by said rods. These plates may then also serve as supports for the ends of the valve column.

As soon as certain voltage valuesgenerally of the order of 10 kv.are exceeded, it maybe advisable to divide the valve into several sections, between which larger insulating distances are left than between the different columns in the same section. Such sections may then also be assembled individually and may form a kind of construction elements and a standard type which may be assembled in a larger or smaller number according to the desired total voltage. Such elements may-with respect to the longitudinal direction of the columns-be placed either side by side or end to end. The former arrangement may in certain. cases be preferable when the valve is freely mounted in an oil receptacle to-' gether with cooperating members, for instance a transformer or different parts of a voltage regulator. The reinforcing end plates are then simply mounted to form extensions of one another and the limit between the different section may be marked simply by a somewhat increased distance between the columns. The arrangement of the sections end to end may especially be preferred when the valve forms a separate piece of construction, for instance enclosed in a tube of insulating material. The plates then preferably form partitions between the diiferent sections; although they should permit the circulation of a cooling medium between these sections. In some cases the plates may be combinedto form one single helicoidal plate. The insulating rods are preferably formed by two concentric tubes, 'the inner of which traverses several plates, while the outer ones form distance pieces between the plates.

One form of the invention is diagrammatically illustrated in the accompanying drawing, in which Fig. 1 shows details of three adjacent column groups arranged end to end in a side view, Fig. 2 a corresponding end View and Fig. 3 a cross section, while Fig. 4 is a cross-section showing a modified form of the invention.

In Figs. I-3, the columns as such are designated by It). Only one column is shown in detail in Fig. 1, composed of valve plates by intermediary plates 2, the latter provided with protuberances 3 in a manner known per se for creating interspaces, through which the cooling medium may circulate. For the other columns and in Fig. 2 only the external contours are indicated by dash and dotted lines. The columns are placed between plates 4 of insulating material together with springs 5 which maintain an appropriate contact pressure between the valve plates 1 and the intermediary plates 2 which also serve to transmit the current.

As shown in Fig. 3, the columns are in this form mounted in a circular row around a. free inner space. Each column is guided laterally by three rods of insulating material, for instance in the form of Bakelite tubes. rods which are placed inside the columns, are, however, common to two columns so that their number will be equal to that of the columns. Each such rod is composed of two concentric tubes 6, l, the inner G of which traverses several of the plates 4, as is seen in Fig. 2, possibly all such plates, while the outer tube 1 only lies between two adjacent plates and there serves as a distance piece. The outer rods 8 consist, in the form shown, of simple tubes and traverse preferably all the plates.

' The plates 4 are as shown preferably annular solas to form a central through channel, through which a cooling medium, generally oil, may circulate freely. In some cases this channel may be-annular in section and internally limited by a through air channel, or it may be annular only at the ends and surround air pockets, from which the heat may be carried off by air currents. The plates 4 may at their outer periphery have recesses 9 between the bolts 8, through which recesses the oil may flow in a direction oppositeto that of the central channel.

As'stated above the plates may in some cases be. combined to' form one single helicoidal plate and such an arrangement is illustrated at Fig. 4, where the plates separating the different sections of the tube are shown combined as one single helicoidal plate 24.

We claim as our invention:

-l. -A high voltage dry valve apparatus com prising a plurality of geometrically parallel, electrically'series-connected columns of electrically series-connected dry valve plate elements, said columns being arranged in at least one circular row around a central cooling channel, insulat- I Those of these prising a plurality of geometrically parallel, electrically series-connected columns of electrically series-connected dry valve plate elements, insulating rods parallel to said columns, adapted to guide them laterally and to permit free circulation of a cooling medium in Contact with said plate elements, and an insulating wall forming a continuous helicoidal surface adapted to guide said columns and insulating rods at spaced intervals and to separate series-connected groups of columns from each other.

3. A high voltage dry valve apparatus comprising a plurality of geometrically parallel, electrically series-connected columns of electrically series-connected dry valve plate elements, in-

.sulating rods consisting of concentrical tubes parallel to said columns, adapted to guide them laterally and to permit free circulation of a cooling medium in contact with said plate elements, spaced insulating Walls adapted to guide said rods laterally and to separate series-connected groups of columns from each other, the external-,ones of said concentric tubes forming distance pieces between said walls, the internal ones of said tubes extending through said walls and connecting columns on opposite sides of said walls;

4.-A high voltage dry valve apparatus comprising a plurality of geometrically parallel, elec-. trically series-connected columns of electrically series-connected dry valve plate elements,'said columns being arranged in at least one circular row around a central cooling channel, an insulating tube surrounding said rows, insulating rods parallel to said columns, at least three such rods being in contact with each column, and the said rods being adapted to guide said columns laterally and to permit free circulation of a cooling medium from said central channel in contact with said plate elements, and insulating plate means in which both ends of said rods are fixed, at least one of said plate means servingito separate said columns from columns under a different mean voltage.

UNO LAMM. ALGOT ARVIDSSON.

REFERENCES CITED The following references are of record in file. of this patent:

UNITED STATES PATENTS the Number Name Date 1,833,332 Peter Nov. 24, 1931 1,845,573 Ackerly Feb. 16, 1932 "2,090,806 Osawa Aug. 24, 1937 

